- The brain has natural rhythms called brain waves. An electroencephalogram (EEG) can record these rhythms. When people identify the picture of a familiar object shown on a computer screen, the communication between certain regions of the brain increases. An EEG can detect these communication brain waves. Transcranial magnetic stimulation (TMS) can affect these brain waves by slightly changing the brain s rhythms. Researchers want to see if changing brain rhythms with TMS interferes with the ability to identify pictures of familiar objects. This study will provide more information about how TMS can affect brain waves and behavior.